Figure 2. TERRA expression in murine oocytes, early cleavage and blastocyst stage with regards to maternal age. (A) The TERRA signal was detected by RNA-FISH on murine oocytes and different cleavage stages of murine early embryos and blastocysts using a probe targeting TERRA’s telomeric track (green), DAPI=blue. Zoom areas are shown, where only the bright puncta correspond to TERRA transcripts. (B) Graph shows the quantification of the mean number of TERRA spots in all developmental stages in the young donor group (mean+s.d., n=number of samples). (C) Zoom areas corresponding to the inner cell mass (ICM) and trophoectoderm (TE) are shown. (D) Graph represents the mean number of TERRA spots in the ICM and TE (mean+s.d., n=number of blastocysts). (E) Graph shows the quantification of the mean number of TERRA spots in all developmental stages in the three differently aged donor groups (6, 12 and 24 months old) (mean+s.d., n=number of samples). Total number of foci and nuclei used for the analysis are indicated. Scale bar: 10 μm. The Student’s t-test was used for all statistical analysis (*p<0.05, **p < 0.01, and ***p<0.001).